Silica-based, glass, such as soda-lime-silica glass, is prevalent in the manufacture of glass containers and other articles. Molten glass used to make such articles is conventionally prepared by inching a mixture of glass-forming materials known as a batch in a continuous tank furnace. The resulting molten glass typically contains an undesirable amount of gas bubbles which need to be removed. The process of removing gas bubbles from molten glass is commonly referred to as “refining,” and typically involves maintaining the molten glass at a relatively high temperature for a sufficient duration to allow the gas bubbles in the molten glass to rise to a free surface thereof and escape. After the glass has been refined it is typically conditioned by reducing the temperature of the molten glass to a suitable temperature for use in downstream glass forming operations where the molten glass may be formed into glass containers and other products.
A general object of the present disclosure, in accordance with one aspect of the disclosure, is to provide a process for manufacturing glass in which excess heat applied to the molten glass during an upstream stage of the process is subsequently recovered in a downstream stage of the process. For example, excess heat applied to the molten glass during the melting and/or refining stages of the glass manufacturing process may be subsequently recovered from the molten glass during the conditioning stage and used to heat another stream of molten glass or to melt additional glass-forming materials. An apparatus is also provided that is configured to carry out such processes.
The present disclosure embodies a number of aspects that can be implemented separately from or in combination with each other.
An apparatus for manufacturing glass in accordance with an aspect of the disclosure includes: a first end and an opposite second end, an inlet for receiving molten glass, an outlet for discharging molten glass, a radially inner flow channel extending between the first and second ends, a radially outer flow channel in fluid communication with the inner flow channel, and an opening for receiving one or more solid glass-forming materials and for introducing the glass-forming materials into molten glass that is flowing within one of the inner or outer flow channels or between the inner and outer flow channels. The inner and outer flow channels are physically separated from each other by a common wall that is configured to allow heat transfer to occur between molten glass flowing through the inner flow channel and molten glass flowing in the opposite direction through the outer flow channel.
In accordance with an aspect of the disclosure, there is provided a process for manufacturing glass including: (a) providing a glass precursor composition, (b) heating the glass precursor composition to a first temperature as the precursor composition flows through a first flow channel in a first direction, (c) removing gas bubbles from the glass precursor composition, (d) flowing the glass precursor composition from the first flow channel into a second flow channel, (e) introducing one or more glass-forming materials into the glass precursor composition to form a final glass composition having a second temperature lower than the first temperature, and (f) flowing the final glass composition through a second flow channel in a second direction opposite the first direction. The one or more glass-forming materials are introduced into the glass precursor composition in step (e) such that excess heat is transferred from the glass precursor composition to the one or more glass-forming materials to dissolve the one or more glass-forming materials into the glass precursor composition and form the final glass composition. When the final glass composition flows through the second flow channel in step (f), heat is transferred by conduction through a common wall physically separating the first and second flow channels from each other and countercurrent heat exchange occurs between the glass compositions flowing in opposite directions through the first and second flow channels.
In accordance with an aspect of the disclosure, there is provided a process for manufacturing glass including: (a) providing a plurality of solid glass batch materials in amounts according to a final desired glass batch composition, (b) heating at least a portion of the plurality of solid glass batch materials as the materials flow through a first flow channel in a first direction to produce molten glass, (c) flowing the molten glass from the first flow channel into a second flow channel, and (d) flowing the molten glass through the second flow channel in a second direction opposite the first direction. Heat is transferred by conduction through a common wall radially separating the first and second flow channels from each other and countercurrent heat exchange occurs between the glass batch materials and the molten glass flowing in opposite directions through the first and second flow channels.
In accordance with an aspect of the disclosure, there is provided a process for manufacturing glass including: (a) flowing unrefined molten glass through a first flow channel in a first direction, (b) heating the unrefined molten glass to a first temperature as the molten glass flows through the first flow channel, (c) removing gas bubbles from the unrefined molten glass to produce refined molten glass, and (d) flowing the refined molten glass through a second flow channel in a second direction opposite the first direction. When the refined molten glass flows through the second flow channel in step (d), heat is transferred by conduction through a common wall radially separating the first and second flow channels from each other and countercurrent heat exchange occurs between the molten glass flowing in opposite directions through the first and second flow channels.